From 13eb1416bab89a9923cd880a9a0e626f17ae95fc Mon Sep 17 00:00:00 2001
From: Tom Fifield <tom@tomfifield.net>
Date: Tue, 17 Sep 2024 10:10:46 +0800
Subject: [PATCH] PMSA0031 sensors require ~3secs before coming up on I2C

As reported by @MALAONE1 and debugged by @shodan8192 , PMSA0031s
on a RAK4631 take 3 seconds before they can become detectable on I2c.

Add a delay(4000) before I2C scan if the air quality sensor pin
is defined.

Fixes https://github.com/meshtastic/firmware/issues/3690
---
 src/main.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/main.cpp b/src/main.cpp
index 2c8c0dcb83..0de25538fe 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -393,6 +393,7 @@ void setup()
     // RAK-12039 set pin for Air quality sensor
     pinMode(AQ_SET_PIN, OUTPUT);
     digitalWrite(AQ_SET_PIN, HIGH);
+    delay(4000); // Detectable on I2C after ~3 seconds.
 #endif
 
 #ifdef T_DECK